title: Lactation reduces stress-caused dopaminergic activity and enhances GABAergic activity in the rat medial prefrontal cortex.
abstract: We investigated the effect of restraint on the release of dopamine, GABA and glutamate in the medial prefrontal cortex (mPFC) of lactating compared with virgin Wistar female rats; besides the expression of D1, neuropeptide Y Y2, GABA receptors and corticotropin-releasing factor (CRF). Results from microdialysis experiments showed that basal dopamine and GABA, but not glutamate, concentrations were higher in lactating rats. In virgin animals, immobilization caused significant increase in dopamine, whereas GABA was unchanged and glutamate reduced. In lactating animals, restrain significantly decreased dopamine concentrations and, in contrast to virgin animals, GABA and glutamate concentrations increased. We found a higher expression of CRF, as well as the D1 and neuropeptide Y Y2 receptors in the left mPFC of virgin stressed rats; also, only stressed lactating animals showed a significant increase in immunopositive cells to GABA in the left cingulate cortex; meanwhile, a significant decrease was measured in virgin rats after stress in the left prelimbic region. The increased inhibition of the mPFC dopamine cells during stress and the down-regulated expression of the neuropeptide Y Y2 receptor may explain the lower CRF and hyporesponse to stress measured in lactating animals. Interestingly, participation of mPFC in stress regulation seems to be lateralized.
authors.affiliation: Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México, Apdo. Postal 70250, Delegación Coyoacán, 04510, México, D.F. México, Mexico.
authors.forename: Virginia
authors.initials: V
authors.lastname: Arriaga-Avila
authors.forename: Eduardo
authors.initials: E
authors.lastname: Martínez-Abundis
authors.forename: Beatriz
authors.initials: B
authors.lastname: Cárdenas-Morales
authors.forename: Octavio
authors.initials: O
authors.lastname: Mercado-Gómez
authors.forename: Erick
authors.initials: E
authors.lastname: Aburto-Arciniega
authors.forename: Alfredo
authors.initials: A
authors.lastname: Miranda-Martínez
authors.forename: Keith M
authors.initials: KM
authors.lastname: Kendrick
authors.forename: Rosalinda
authors.initials: R
authors.lastname: Guevara-Guzmán
mesh_terms: D000818:Animals; D003346:Corticotropin-Releasing Hormone / Q000378:metabolism; D004298:Dopamine / Q000378:metabolism*; D015536:Down-Regulation / Q000502:physiology; D005260:Female; D018698:Glutamic Acid / Q000378:metabolism; D007774:Lactation / Q000378:metabolism*; D008032:Limbic System / Q000378:metabolism; D017551:Microdialysis; D017397:Prefrontal Cortex / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D017447:Receptors, Dopamine D1 / Q000378:metabolism; D017476:Receptors, Neuropeptide Y / Q000378:metabolism; D013315:Stress, Psychological / Q000378:metabolism*; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
chemical_list: D017447:Receptors, Dopamine D1; D017476:Receptors, Neuropeptide Y; C095889:neuropeptide Y2 receptor; D018698:Glutamic Acid; D005680:gamma-Aminobutyric Acid; D003346:Corticotropin-Releasing Hormone; D004298:Dopamine